When multiple child scene components are selected and their parent is rotated 90 degrees about Z, attempting to use the transform gizmo will move the components in the wrong direction relative to the selected axis.
This does not occur if only a single child component is selected.
- Select/move only one child scene component at a time (this seems to function as expected).
- With multiple child scene components selected, use the numeric slider widget in the Blueprint editor's details panel to adjust the coordinates along the desired axis, or just type it in directly.
- Drag an instance of the Blueprint class into the current scene, select the child scene component(s) you wish to translate, and use the level editor's gizmo to move them (this also seems to function as expected). After that, you can choose "Apply Instance Changes to Blueprint" in the Details tab to reflect the changes back up to the Blueprint class.